Q. The ratio of the rate of diffusion of helium and methane under identical condition of pressure and temperature will be
A) 4
B) 0.2
C) 2
D) 0.5
Explanation
(c)
By Graham’s diffusion law,
$\ \ \frac{r_{He}}{r_{{CH}_{4}}} = \sqrt{\frac{M_{{CH}_{4}}}{M_{He}}}$
$M_{{CH}_{4}} = 12 + 4 = 16$
$\ \ M_{He} = 4$
$\frac{r_{He}}{r_{{CH}_{4}}} = \sqrt{\frac{16}{4}} = \sqrt{\frac{4}{1}} = 2$
Thus, the ratio of rate of diffusion of He and ${CH}_{4}$ is 2.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.